feature: detect cyclic recursion in partials (#347)

closes #242
PhpGt · Jun 10, 2022 · e787874 · e787874
1 parent ebba1b0
commit e787874
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diff --git a/src/CyclicRecursionException.php b/src/CyclicRecursionException.php
@@ -0,0 +1,4 @@
+<?php
+namespace Gt\DomTemplate;
+
+class CyclicRecursionException extends DomTemplateException {}
diff --git a/src/PartialExpander.php b/src/PartialExpander.php
@@ -25,6 +25,9 @@ public function expand(Element $context = null):array {
 			}
 
 			$partialDocument = $this->partialContent->getHTMLDocument($extends);
+			if(isset($partialDocumentArray[$extends])) {
+				throw new CyclicRecursionException("Partial '$extends' has already been expanded in this document, expanding again would cause cyclic recursion.");
+			}
 			$partialDocumentArray[$extends] = $partialDocument;
 			$context = $partialDocument;
 		}

diff --git a/test/phpunit/PartialExpanderTest.php b/test/phpunit/PartialExpanderTest.php
@@ -4,6 +4,7 @@
 use Gt\Dom\Element;
 use Gt\Dom\HTMLDocument;
 use Gt\DomTemplate\CommentIni;
+use Gt\DomTemplate\CyclicRecursionException;
 use Gt\DomTemplate\PartialContent;
 use Gt\DomTemplate\PartialContentFileNotFoundException;
 use Gt\DomTemplate\PartialExpander;
@@ -119,4 +120,19 @@ public function testExpand_multipleDataPartialElements():void {
 		self::expectExceptionMessage("The current view extends the partial \"base-page\", but there is more than one element marked with `data-partial`.");
 		$sut->expand();
 	}
+
+	public function testExpand_detectCyclicRecursion():void {
+		$document = DocumentTestFactory::createHTML(DocumentTestFactory::HTML_EXTENDS_PARTIAL_CYCLIC_RECURSION);
+		$partialContent = self::mockPartialContent(
+			"_partial", [
+				"extended-page-1" => DocumentTestFactory::HTML_EXTENDS_PARTIAL_CYCLIC_RECURSION_1,
+				"extended-page-2" => DocumentTestFactory::HTML_EXTENDS_PARTIAL_CYCLIC_RECURSION_2,
+				"partial-base" => DocumentTestFactory::HTML_PARTIAL_VIEW,
+			]
+		);
+		$sut = new PartialExpander($document, $partialContent);
+
+		self::expectException(CyclicRecursionException::class);
+		$sut->expand();
+	}
 }
diff --git a/test/phpunit/TestFactory/DocumentTestFactory.php b/test/phpunit/TestFactory/DocumentTestFactory.php
@@ -747,6 +747,33 @@ class DocumentTestFactory {
 </main>
 HTML;
 
+	const HTML_EXTENDS_PARTIAL_CYCLIC_RECURSION = <<<HTML
+<!-- extends=extended-page-1 -->
+<div>
+	This is the deepest part of the cyclic recursion.
+</div> 
+HTML;
+
+
+	const HTML_EXTENDS_PARTIAL_CYCLIC_RECURSION_1 = <<<HTML
+<!--
+extends=extended-page-2
+-->
+<div>
+	This HTML extends page 2. 
+</div>
+<div data-partial>Extended page is injected here</div>
+HTML;
+
+	const HTML_EXTENDS_PARTIAL_CYCLIC_RECURSION_2 = <<<HTML
+<!--
+extends=extended-page-1
+-->
+<div>
+	This HTML extends page 1.
+</div>
+<div data-partial>Extended page is injected here</div>
+HTML;
 
 	public static function createHTML(string $html = ""):HTMLDocument {
 		return HTMLDocumentFactory::create($html);